Global Carbon Dioxide Hit Record Levels in 2007

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GENEVA, Switzerland, November 25, 2008 (ENS) - Climate-heating greenhouse gases continue to increase in the atmosphere, and last year, global concentrations of carbon dioxide again reached the highest levels ever recorded, according to an annual report released today by the World Meteorological Organization.

Greenhouse gases trap the Sun's radiation within the Earth's atmosphere causing it to warm. Human activities, such as fossil fuel burning and agriculture, are major emitters of the gases, which scientists recognize as drivers of global warming and climate change.

The WMO Global Atmosphere Watch coordinates the measurement of greenhouse gases in the atmosphere through a network of observatories located in more than 65 countries.

The measurements are published annually in the WMO's "Greenhouse Gas Bulletin."

The new figures were released just days ahead of the annual UN Climate Change Conference, taking place this year in Poznan, Poland from December 1-12.

It constitutes the half-way mark of a two-year negotiating process, set to culminate in an ambitious international climate change deal in Copenhagen next year that will take over from the Kyoto Protocol limiting greenhouse gas emissions, which expires in 2012.

In Poland, negotiators will take stock of the progress made in the first year of the talks and outline what needs to be done to reach agreement at the end of 2009.

After water vapor, the four most prevalent greenhouse gases in the atmosphere are carbon dioxide, methane, nitrous oxide and chlorofluorocarbons, CFCs, ozone-damaging chemicals once widely used as refrigerants.

CFC levels are now slowly dropping due to emissions reductions set under the United Nations Montreal Protocol on Substances that Deplete the Ozone Layer that entered into force in 1989.

Carbon dioxide reached 383.1 parts per million (ppm), an increase of 0.5 percent from 2006, according to the latest numbers in the World Meteorological Organization report.

Concentrations of nitrous oxide also reached record highs in 2007, up 0.25 percent from the year before.

Methane levels increased 0.34 percent, exceeding the highest value so far, which was recorded in 2003.

Using the annual greenhouse gas index issued by the U.S. National Oceanic and Atmospheric Administration, NOAA, the total warming effect of all long-lived greenhouse gases was calculated to have increased by 24.2 percent since 1990 and by 1.06 percent from the previous year.

Since the mid-18th century, carbon dioxide concentrations in the atmosphere have risen 37 percent, the report states.

"Population growth and urban development worldwide continue to increase the use of fossil fuels, such as oil, coal and natural gas, which emit carbon dioxide and other gases into the atmosphere. At the same time, the clearing of land for agriculture, including deforestation, is releasing carbon dioxide into the air and reducing carbon uptake by the biosphere," the World Meteorological Organization states in its report.

There is a glimmer of good news concerning the greenhouse gas methane. While the atmospheric concentrations of other gases are increasing steadily, the growth rate of methane concentrations has slowed over the past decade.

The rise of six parts per billion from 2006 to 2007 is the highest annual methane increase observed since 1998. It is still too early to state with certainty, the scientists said, that this latest increase is the start of a new upward trend in methane levels.

Meanwhile, a consortium including the UN Food and Agriculture Organization today said that Africa as a continent is a carbon sink - the continent is absorbing more carbon dioxide from the atmosphere than it is releasing.

CarboAfrica found that Africa contributes less than four percent of the global emissions from fossil fuels, but accounts for 17 percent and 40 percent respectively of gas emissions emanating from deforestation and fires.

But the most important element, said CarboAfrica coordinator Riccardo Valenti, is the balance between carbon captured through photosynthesis by Africa's forests and savannas and gas released into the atmosphere, according to the research findings, prepared by scientists from 15 institutions.

"Our evidence so far indicates that Africa seems a 'carbon sink,' meaning that it takes more carbon out of the atmosphere than it releases," said Valenti. "If confirmed, this implies that Africa contributes to reducing the greenhouse effect, thus helping mitigate the consequences of climate change."

{Photo: The Bruce Mansfield coal-fired power plant in Pennsylvania by Kiyo Komoda}